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libraries/hd44780/examples/ioClass/hd44780_I2Cexp/SoftwareWire/SoftwareWire.ino

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+// vi:ts=4
+// ----------------------------------------------------------------------------
+// SoftwareWire - how to use SoftwareWire library with hd44780_I2Cexp
+// Created by Bill Perry 2020-01-01
+// bperrybap@opensource.billsworld.billandterrie.com
+//
+// This example code is unlicensed and is released into the public domain
+// ----------------------------------------------------------------------------
+//
+// Demonstrates how to use the SoftwareWire library to allow using different
+// Arduino pins for SDA and SCL signals.
+//
+// Sketch prints "Hello, World!" on the lcd
+//
+// If initialization of the LCD fails and the arduino supports a built in LED,
+// the sketch will simply blink the built in LED.
+//
+// WARNING:
+//  The SoftWareWire developers made a major change to the library June 2018
+//  which is in the subsequent 1.5.1 release that causes it be unusable by
+//  the hd44780 library.
+//  Until this change is backed out, you will not be able to use 
+//  SoftWareWire beyond version 1.5.0 with the hd44780 library.
+//  This sketh will do a check to try to detect the incompatibilty issue
+//  and will error off with a compiler error when detected.
+//  See this github issue for details:
+//  https://github.com/Testato/SoftwareWire/issues/28
+//
+// NOTE:
+// Using the SoftwareWire library is not necessary on the espXXXX platform as
+// that platform already has the ability to configure the pins used in the
+// Wire library.
+// On the esp platforms, include <Wire.h> and set the pins by passing them to 
+// Wire.begin(sda, scl) *before* calling lcd.begin()
+//
+//
+// ----------------------------------------------------------------------------
+
+// define the Arduino pins you want to use for sda and scl signals
+// use any Arduino pins you want,
+// this uses same pins as the i2c h/w pins (SDA, SCL)
+const int sda=SDA, scl=SCL;
+
+#include <SoftwareWire.h>	// make sure to not use beyond version 1.5.0
+// Check for "new" SoftwareWire that breaks things
+#if defined(TwoWire_h)
+#error incompatible version of SoftwareWire library (use version 1.5.0)
+#endif
+
+SoftwareWire Wire(sda,scl); // Create Wire object using desired Arduino pins
+
+#include <hd44780.h>
+#include <hd44780ioClass/hd44780_I2Cexp.h>
+hd44780_I2Cexp lcd; // declare lcd object and let it auto-configure everything.
+
+void setup()
+{
+int istatus;
+
+  istatus = lcd.begin(16,2);
+  if(istatus)
+  {
+	// LCD initalization failed.
+	// handle it anyway you want
+	lcd.fatalError(istatus); // blinks error code on built in LED
+  }
+  lcd.print("Hello, World!");
+  lcd.setCursor(0,1);
+  lcd.print("SoftwareWire");
+}
+
+void loop() { }